1. Field of the Invention
This invention relates to a center pivot suspension distribution system and more particularly to a center pivot system having the capacity to distribute liquid manure or a liquid containing suspended solid particles over a field. The center pivot system may also be used to distribute irrigating water over the field.
2. Description of the Related Art
Prior liquid/solid distribution systems do not meet the Environmental Protection Agency (EPA) or National Resource Conservation Service (NRCS) requirements for appropriate uniform distribution. The assignor of the instant invention previously developed a suspension distribution system for distributing a liquid suspension containing solid particles and the same is described in U.S. Pat. No. 3,901,442. The apparatus of U.S. Pat. No. 3,901,442 did provide a substantially uniform distribution and did allow solids to pass through the nozzles, but required the use of a mechanical cam which cycled the air pressure to air solenoids which controlled valves which operated large sprinkler guns located on top of the span. Each cam was connected to a gun and was designed to limit the operating time that the gun was operating. By utilizing a mechanical cam that constrains the operating time, the guns located near the pivot had an even coverage and allowed a minimum nozzle diameter of 0.47 inches.
Systems other than that described in U.S. Pat. No. 3,901,442 do not have sprinkler orifices that allow solids up to 0.47 inches to pass through them, thereby causing the nozzles to plug. By attaching smaller sprinklers mounted to the top of the irrigation line and adjusting the size of the orifices on each nozzle with respect to its position from the pivot point, uniformity was accomplished, but solids plugged the nozzle orifices.